Fractures located near the proximal or distal ends of a patient's bone are often problematic for the operating surgeon to fix.
With respect to the femur, proximal fractures commonly occur in the femoral neck, and in the inter-trochanteric region. Distal femur fractures that occur between the femur and the condyles are termed “supracondylar fractures”. Distal fractures occurring in one or more of the condyles are termed a “condylar” or “intercondylar” fracture.
Distal femur fractures are often difficult for an orthopedic surgeon to fix because of their proximity to the knee and their frequent association with patients having a total joint replacement covering the end of the bone and/or those suffering from osteoporosis. More specifically, affixing pins, screws, plates, and/or an intramedullary nail in a brittle bone having low mineral density, can often lead to undesirable results.
Prior attempts to treat fractures utilizing an intramedullary nail attached to an internal blade have been described. Prior descriptions are found in U.S. Pat. No. 6,572,620 (“Schon et al.”) and U.S. Pat. No. 6,652,529 (“Swanson”), for example. These references are hereby expressly incorporated herein by reference in their entireties.
Schon et al. is directed to methods of affixing two adjoining bones together where the intramedullary nail is implanted into a larger bone (e.g., tibia) and attached to a blade that is positioned into an adjacent smaller bone (e.g., talus). One of the potential disadvantages of the Schon et al. design is that the final configuration is substantially an “L-shape” implant, where the intramedullary nail is secured through a passageway adjacent to the proximal end of the blade (See Schon et al. FIG. 1). One of the disadvantages to the “L-shape” configuration is that it may result in a weaker implant as the intramedullary nail is not centrally secured to the blade, or substantially so. Accordingly, overly long intramedullary nails may be required to maintain the general “L-shape.” Another disadvantage to the design taught by Schon et al. is that it is not optimal for treating fractures located near the distal end of a single bone as the coupling mechanism disclosed extends past the lower surface of the blade. This type of coupling mechanism prevents the surgeon from positioning the blade to the more distal parts of the larger bone, where it may be needed for more distal fractures.
In an attempt to address distal femoral fractures, Swanson discloses an intramedullary nail, having a blade passage, configured to receive a blade, wherein the blade passage is located in the proximal end of the nail “some distance” away from the proximal tip of the nail. (See Swanson, col. 6, lines 18-20) Essentially this assembly results in an upside down cross-shape with the proximal end of the intramedullary nail extending past the blade into the distal femur. (See Swanson, FIG. 2). While not being in a general “L-shape” Swanson's design, like that of Schon et al., limits the surgeon's ability to treat fractures located very close to the distal end of the femur, such as condylar and intercondylar fractures. This is because the proximal end of the intramedullary nail extends below the lower surface of the blade, thereby preventing a surgeon from positioning the blade to the more distal parts of the femur. Another disadvantage of the Swanson design is that the distal portion of the intramedullary nail includes a passageway for the blade to pass through. (See Swanson, FIGS. 2 and 3). This passageway is an area of weakness and is more likely to lead to a fatigue fracture of the intramedullary nail. Furthermore, this passageway necessitates a cross-like formation such that the distal tip of the intramedullary nail protrudes past the blade.
In light of the prior art, there is a need in the art for new assemblies and methods for implanting blade and IM nail systems in the distal or proximal end of a patient's bone. Accordingly, one of the objects of the invention is to provide an intramedullary rod and blade assembly that can be implanted more distally or proximally than prior systems and thus fix more distally located fractures on a large bone than the prior art currently allows. A further object of the invention is to provide assemblies that includes an intramedullary nail and blade, each configured to couple with one another without the use of a blade passageway in the intramedullary nail.